Constant force yarn tensioning means



y 15, 1955 B. LERMONT 2,745,609

CONSTANT FORCE YARN TENSIONING MEANS Filed Oct. 14, 1953 2 Sheets-Sheet l INVENTOR.

BASIL LERMONT EM hlbww ATTO RN EYS May 15, 1956 -r 2,745,609

CONSTANT FORCE YARN TENSIONING MEANS Filed Oct. 14, 1953 2 Sheets-Sheet 2 INVENTOR. BASIL LERMONT ATTORN EYS h BY United States Patent 2,745,609 Patented May 15,

ice

7 2,745,609 7 CONSTANT FORCE YARN TENI ONING MEANS Basil Iberrnont, New York, N. Y. I Application October 14, 1953, Serial No. 385,905

' Claims. 01. 242-149 The present invention relates to yarn tensioning devices and, more particularly, to yarn tensioning devices that will maintain yarn under constant tension during winding, knitting, or other operations. It is to be understood that the word yarn as used herein includes any thread, whether it be synthetic such as nylon, rayon, etc. or natural, such as cotton, wool, etc.

The invention further relates to a constant force, yarn tensioning device that is adjustable, so that the constant tension which it induces in yarn for any given adjustment can be varied as desired to provide variations in tension to suit the properties of different yarns and the character of the goods being knitted with the yarns.

The invention further relates to an automatic stop control mechanism for a winding, knitting machine, or the like, including means effect ve to stop the machine whenever the tension in a yarn exceeds a predetermined constant tension for which the stop control mechanism has been set.

The invention still further relates to a device adapted to be alternatively used as a yarn tensioning means, or as a tension-responsive control for a stop mechanism, or to be used to simultaneously control yarn tensioning and control a stop mechanism.

The principal object of the invention is to provide a yarn tensioning device that is simple in construction, but which will nevertheless maintain a constant tension upon yarn being knitted in a circular knitting machine, or other type of machine, for knitting various fabrics such as hosiery, cylindrical tubing, etc.

Another object is to provide a constant force, yarn tensioning device that can be adjusted to suit the particular characteristics of the yarn. being knitted and at the same time maintain a selected constant force on the yarn in a given position of adjustment of the device.

Another object of the invention is to provide astop control mechanism for a machine that is responsive to excessive tension in a yarn for effecting automatic stopping of the machine when a'prescribed tension force is exceeded.

A further object of the invention is to provide a constant force, yarn tensioning device for maintaining a predetermined desired constant tension upon yarn during knitting, etc., and which is also adapted to be used as a stop control mechanism operable to interrupt the operation of the machine whenever the tension of the yarn exceeds a given tension setting of the constant tension device.

Other objects and features of the invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a front elevational view of a constant force, yarn tensioning device embodying the principles of the present invention;

Fig. 2 is a left side elevational view of the device shown in Fig. 1; I

Fig. 3 is a front elevational view of a modified form of constant force, yarn tensioning device;

Fig. 4 is a right side elevationalview shown insFig. 3;

Fig. 5; is a front elevational view of an adjustable constant force, yarn tensioning device, which is also adaptable for use as a stop mechanism control device;

Fig. dis a left side elevational view of the device shown in Fig. 5; v i Y Fig. 7 is a fragmentary rear elevational view of the device shown in Fig. 5;

Fig. 8 is an elevational view of one form of spring that may be used in the device of Figs. 5 to 7, the spring being shown in a flat condition to illustrate the long slot formed therein; 1

Fig. 9 is a view of the sideedge of the spring shown in Fig. 8 and particularly illustrating the variation in thickness thereof from one end to the other; I

Fig. 10 is a diagrammatic view illustrating the use of the device shown in Fig. l as a yarn tensioning means, and the use of the device shown in Fig. 5 as a stop mechanism control device;

Fig; ll is a diagrammatic view illustrating the use of the deviceof Fig. 5 as a combined yarn tensioning and stop mechanism control means; and

Fig. 12 is a fragmentary view of a modified form of spring.

Referring now to Figs. 1 and 2, the constant force, yarn tensioning device illustrated therein is generally identified by the numeral 1 and preferably comprises a constant tension spring 2, every increment a, b, c, d, etc., of which is bent upon the same radius of curvature R, and is fully set forth in my prior Patent 2,609,192, granted September 2, 1952 to which reference may be made to ascertain the full and complete manner in which the spring 2 is produced. V

The spring 2 has an end portion 3 which is wound clockwise, as viewed in Fig. l, to form a coil 4 comprising a' plurality of convolutions. The opposite end 5 'ofthe spring? iswound in a counter-clockwise direction, as viewed in Fig. 1, to provide a second coil 6 comprising a plurality of convolutions. Due to the bending of the spring, the coils 4 and 6 are self-winding. The coil 4 is preferably wound upon a cylindrical support or mandrel 7 having a radius slightly greater than the radius R, so that the innermost convolution of the coil 4is slightly expanded from its normal diameter and of the device tightly engaged 'in nonslipping relation with the outer periphery of the mandrel 7. The mandrel 7 has an axial length slightly greater than the width of the spring 2 as'is best shown in Fig. 2. The spring 2 and the mandrel 7 are adapted to be supported, when in use,-by a generally U-shaped mounting bracket 8 including parallel arms 9 and 10 between which the mandrel '7 is disposed. The mandrel 7 is held against rotation relative to the bracket 8 by a pluralityof bolts 11 which extend through suitable openings in the arms 9 and 10 and in the mandrel 7.

The oppositely wound coiled portion 4 and 6 of the spring 2 preferably have the same number of convolutions, and a short slot '12 is formedin the relatively straight portion of the spring which interconnects the two coils. Since each increment of the spring 2 is bent upon the same radius of curvature R, the coiled portions 4 and 6 remain in equilibrium, that is to say, there is no tendency for one coil to cause the other to unwind, notwithstanding the fact that the coils themselves are self-winding and press against each other in the absence of a yarn therebetween. Moreover, since each increment of the coils 4 and 6 is bent upon the same radius of curvature R, the outermost convolutions of the coils 6 and 7 tend to engage each other with a constant vforce deipending upon the dimensions and other physical characteristics of the material constituting the spring" 2. The material it slides through the bite of the coils.

employed to make the spring 2 can be any of the conventional types of spring steel, or an alloy, such as a beryllium copper alloy. The spring may also be formed of 'through the slot 12 and into the bite provided by the eyelet 14 is mounted in a'depending portion 15 of the bracket 8. Itwill be noted from Fig. 1 that the direction 1 of movement of the yarn 13 is indicated by the arrow 16 as from leftto right, so that the frictional engagement between the yarn 13 and the coiled portions of the spring 2 tends to unwind rather than to wind the coils, which latter would have a tendency to slightly increase the fpinching effect of the coils upon the yarn should the direction of movement of the yarn be reversed, Fig; 1 indicates the preferred direction of travel of the yarn, but it is to be understood that the tensioning device 1 may be mounted in a manner such that the direction of travel of the yarn is reversed from that illustrated in Fig.1.

Inasmuch as the coiled ends 4 and 6 of the spring 2 are urged toward each other by a constant force, they automatically apply a constant frictional force against the yarn 13 to maintain a constant tension in said yarn as This tension my be varied from a fraction of an ounce to any extent desired, in accordance with the dimensions and characteristics of the particular material selected to fabricate the spring. Naturally, very thin material will be employed the variable force that must be imposed can be applied by an adjustable constant tension device of the character Instead of having the yarn travel in a direction at right angles to the axis of the coiled ends of the constant tension spring, as in the device 1 shown in Figs. 1 and 2, it is possible to achieve a similar yarn tensioning'result by passing a yarn between the coiled ends of the spring in a direction parallel with the axis of the coils. Thus, in Figs. 3 and 4, a constant force, yarn tensioning device 20 is illustrated which includes a mounting bracket 21 havingparallel arms 22 and 23 between which a mandrel 24,,sifnilar to the mandrel 7, is stationarily mounted by means of a pair of bolts 25. A constant tension spring 26, similar to the spring 2, except that theslot 12 has been omitted, has one end portion 27 wound upon the mandrel 24 to' form a coil 28, inthe same manner as the coil 4. The opposite end 29 of the spring 26 is reversely wound to form a coiled portion 30. Eyelets or thread 4 r a by the coils 28 and 30, which retard movement thereof and thus produce a tension therein. The outer edges of the coiled portions 28 and 30 are preferably rounded as indicated at 34 and 35, respectively, Fig. 4, to prevent the thread 33 from snagging at the edges of the coils.

The rounding of the edges of the coils, as described, makes it possible to mount the yarn tensioning device 20 so that theyarn 33 can move in either direction rela- Since the yarn 33 is engaged for thefull tive thereto. width of the spring 26, a greater friction drag is imposed,

'than would be the case with an identical spring and a the coils, as in- Fig. 1, wherein only theoretical. point,

instead of line, contact is effected by the coils with the yarn.

Figs. 5 to 7 illustrate an adjustable, constant force, yarn tensioning device 40, which includes a generally U-shaped mounting bracket 41, having arms 42 and 43 provided with aligned openings 44 adapted to serve as journals for a shaft 45 non-rotatably secured to a mandrel 46. One end 47 of a spring 48 is wound upon the mandrel 46 to form a coil 49. The opposite end 50 of the spring 48 is wound upon a second mandrel 51 to form a coil 52 wound in the reverse direction to the coil 49. The mandrel 51 is non-rotatably mounted upon-a shaft 53 having ends which project through vertically elongated slots 54 formed in the bracket arms 42 and 43. The purpose of the elongated slots 54 will be explained later. Collars 55 prevent longitudinal movement of the shaft 53 relative to the bracket 41. a

The spring 48 diifers from the springs 2 and 26, previously described, in that it is constructed so that different portions along the length thereof require a different, instead of a constant, force to unwind the same. A spring having the latter characteristics may be made in anumber of ways. For example, spring 48 may be of uniform thickness and width, but bent upon a gradually varying radius from one end to the other, in the manner fully disclosed in my prior patent, supra. If the radius of bending gradually decreases from the end 47 toward the end 50 of the spring 48, then the coils 49 and 52 will not be in equilibrium and the spring 48 will tend to wind up on the mandrel 51 and unwind from the mandrel 46.

Alternatively, the spring 48 may be made of a gradually increasing thickness from one end thereof to the other, as diagrammatically illustrated in Fig. 9. Even with each increment of such spring bent upon a constant radius,

' other words, the force required to unwind the latter type of spring will increase as the radius upon which the spring is bent decreases. Hence, with either type of spring structure, there will be a tendencyfor the spring to automatically wind itself onto the mandrel 51 and to unwind from the mandrel 46.

It will be apparent, therefore, that the effective force at the bite or region where the coils 49 and 52 tend to contact each other will vary in accordance with the relative proportions of the spring constituting the respective coils. Hence, by varying the relative proportions of the spring 48 wound upon the mandrels 46 and 51, the force applied by the coiled portions 49 and 52 to a yarn disposed therebetween, can be adjusted or varied as desired. Means for effecting winding of the spring 48 upon the mandrel 46 is provided in the form of a knob 56 fixed to one end of the mandrel shaft 45. In view of the tendency of the spring 48 to automatically wind upon the mandrel 51, means must be provided to prevent'such action by maintaining the mandrel 46 in a locked position. Thus, a ratchet wheel 57 is fixed to the opposite end of the shaft 45 and a pawl 58 is mounted upon the bracket arm 43 to engage the ratchet toautomatically restrain the mandrel 46 from rotating in a clockwise direction as viewed in Fig. 5, or in a counter-clockwise direction as viewed in Fig. 7. The pawl 58 is pivotally mounted upon a pin 59 and one end of a tension spring 60 is secured to a pin 61 carried by the pawl 53 and the opposite end'of said spring is connected to a pin 62 mounted upon the bracket arm 43. The spring 60 is arranged relative to the pawl 58 so that it continually urges said pawl toward the ratchet 57. The pawl 58 has an extension 63 provided with an operating pin 64 to facilitate manual release of the pawl 58 whenever it is desired to permit a portion of the spring 48 to unwind from the mandrel 46 onto the mandrel 51 to change the tension characteristics of the device 40. On the other hand, it will be apparent that upon rotation of the knob 56 in a counter-clockwise direction to wind a portion of the spring 48 onto the mandrel 46, the pawl 58v will automatically function to lock the mandrel 46 in any desired position of adjustment. It is only when the knob 56 is to be adjusted clockwise that the pawl 58 must be manually released. The elongated slots 54 permit the mandrel 51 to move bodily relative to the bracket 41 as the spring is either wound off or onto said mandrel. Thus, the coiled portions 49 and 52 are always engaged in the absence of a yarn therebetween.

The spring 48, irrespective of its method of formation, is provided with a slot 65 which is of such a length that it will permit substantial adjustment of the spring 48 relative to the mandrels'46 and51, without assuming a position at the bite of the coils wherein it would render the coils ineffective to apply force .to a yarn. In lieu of a single long slot 65, the spring 48 may be provided with a series of spaced, relatively short slots 65a, as shown in Fig. 12. A conventional eyelet 66 is mounted upon the bracket 41 in a position medially of the arms 42 and 43 in order to guide a yarn 67 so that it will be disposed in registration with the slot 65 in the spring 48.

- It will be obvious from the foregoing that the force applied to. the yarn 67 to resist movement thereof will vary in accordance with the position of the knob 56. In order to enable the user of the device to adjust the same for any desired predetermined tension, a dial plate 68 is fixed upon the bracket armj42 by screws 69.. The dial plate 68 bears graduations constituting a scale for indicating the degree of tension being applied by the spring 48 to the yarn 67.

.,Th e yarn tensioning device 40 illustrated in Figs. 5

m7 is unique in that his readily adapted to be converted into a device for controlling a stop mechanism of a knitting or other machine in the event that the tension on a yarn being worked exceeds a predetermined amount. At the same time, the adjustable characteristics of the device 40 may be employed to vary the tension at which the stop mechanism will be set into action. Moreover, the device disclosed in Figs. 5 to 7 may be used as a stop mechanism control independently of its capabilities of also being used as a yarn tensioning device Thus, by way of illustration, of the versatility of the device 48, Fig. shows the device 40 used solely as a stop control mechanism, and in combination with a yarn tensioning device 1 of the character illustrated in Figs. 1 and 2. ,On the other hand, Fig. 11 diagrammatically illustrates the use of the device 40 as a combined yarn tensioning device and stop mechanism control.

With particular reference to Fig. 10, a yarn cone 71 is shown mounted upon a yarn holder 72. A yarn guide 73 is mounted upon a post 74 in a position above the cone 71 so that the yarn strand 13 can be threaded through the guide 73 in a manner to readily unwind from the cone 71. The yarn 13 is threaded through the tensioning device 1 in the manner illustrated in Fig. 1, and is further threaded through an eyelet 75 carried by a yarn guide finger 76 secured to the shaft 53 associated with the mandrel 51. The yarn guide finger 76 is shown in dot-and-dash lines in Figs. 5 and 6 and may be secured to the shaft 53, or omitted, depending upon theme to. which the device 441' is-to be put." The 'yarn 13 extends from the eyelet to needles 77 carried by a conventional needle cylinder 78 having the usual bevelled drive gear 79 at the lower end, thereof. I

it will be noted from Fig. 10 that the yarn guide finger 76 is inclined upwardly. in a direction away from the shaft 53. An electrical contact 80, which may be in the form of a strip'or bar, is positioned so'that it is normally engaged by the yarn guide finger .76. A conductor 31 is connected with the contact80, and the device 40 may be grounded by another conductor 82, the conductors 81 and 82 being associated with an electric motor or other means (not shown) forefliecting a drive of the cylinder 78 through the gear 79. 1

It will be apparent that the yarn guide finger 76' and the contact 89 function as a yarn tension responsive switch, which controls the driving of the cylinder 78 and therefore acts as a stop mechanism control device. it will be apparent that when the tension in the yarn 13 between the needles 77 and the device 1 is such that it exceeds the tension for which the device 40.is set, the yarn guide finger 76 will be caused by the yarn to rotate in a counter-clockwise direction as viewed in Fig. 10, and thereby move the yarn guide finger 76 out of engagement with the contact to thereby interrupt the electrical circuit to the motor (not shown) driving the machine. The degree of force required to effect movement of the yarn guide finger 76 will depend upon the adjustment of the device 40 and the length of the finger 76, since the tension in the yarn 13 must be such as to overcome the resistance offered to unwinding of the spring 48, by the particular portion of the spring which is disposed tangent to the coil 52. In ordinary operation, of course, the device 1 will normally maintain a constant tension in the yarn 13. However, should the tensionin the yarn between the device 1 and the needles 77 become such as to exceed that for which the device 40 is set, then the yarn will actuate the control finger 76 and the machine will be stopped, as described'hereinbefore.

Fig. 11 illustrates the yarn 67 extending through the eyelet 75 of the yarn guide finger76, said finger, for purposes of diagrammatic illustration, beingshown as have I ing an extension 76a which is adapted to engage the contact 80. As the yarn 67 passes between the coils 49 and 52 a constant force will be applied thereto depending upon the adjustment of the device 40, whereby a constant tension will be maintained in said yarn. However, should the tension in the yarn 67 exceed that for which the device 49 has been set, then the yarn guide finger 76 will be caused to rotate counter-clockwise, away from the contact 80, to interrupt the circuit to the motor (not shown), in the same manner as described in connection with Fig. 10. The advantages of the device 40 over the devices 1 and 26 are many fold. The device 40 is adjustable, within limits, to impart various degrees of constant tension to the yarn, instead of a single constant force, and, moreover, is adapted to serve not only as a yarn tensioning device, but also as an automatic control for stopping a machine when the tension in the yarn exceeds that for which the device has been set.

It will be understood that the yarn guide finger 76 and its associated mandrel 51 and bracket 41 may be employed with a constant tension spring, such as the spring 2 or 26, in lieu of being used with a variable tension or ad-' justable spring such as the spring 48. In this event of course, the knob 56, dial 68, ratchet 57, and pawl 58 are not required in the assembly, but the mandrel 46 will then be fixed relative to the bracket 41 by use of bolts such as the bolts 11 or 25.

It would be understood that various changes may be in the details of construction and arrangement of the yarn tensioning devices, etc. described hereinbefore, without departing from the principles of the invention or the scope of the annexed claims.

which the yarn guide means is, positioned to guide the yarn in a direction generally transverse to the axis of the coils.

3. A yarntensioning device, as defined in claim 1, in

. which the yarn guidemeans is positioned to guidefthe yarn in a direction substantially parallel with the axis of the coils. t V 7 4. A yarn tensioning device as defined in claim 3, in

which the edges of the confronting convolutions of the coils are rounded to prevent the yarn' from snagging there- 5,. A constant force, tensioning device, comprising: a constant tension spring having the ends thereof wound in opposite directions to form reversely wound coils having outermost convolutions adapted to engage each other With a constant pressure; a support; means mounting said coils on said'support; and means positioned to guide a yarn into place between said outermost convolutions.

6. A yarn tensioning device, comprising: a constant tension spring having the ends thereof wound in opposite directions to form reversely wound coils having outermost convolutions adapted to engage each other with a constant force; a support; means mounting said coils on said support, said coils being interconnectedby a relatively straight portion of the spring, said relatively straight spring portion having a passageway formed therein for yarn and located in a plane substantially common to that of the area of engagement of the confronting convolutions of the coils; and means for guiding a yarn into. said passageway. l 7

7. A yarn tensioning devicefcomprising: a spring having the ends thereof wound in opposite directions to form reversely wound coils having outermost convolutions confronting each other and adapted to engage each other with a predetermined force; a mandrel, one of said coils being wound upon said mandrel; a bracket; means nonrotatably securing said mandrel to said bracket; and means for guiding a yarn for passage into the bite of said coils;

8. A constant force, yarn tensioning device, comprising: a constant tension spring having the ends thereof wound in opposite directions to form reversely wound coils having outermost convolutions confronting each other and adapted to engage each other with a constant force; a mandrel, one of saidcoils being wound upon said mandrel; a bracket; means nonrotatably securing said mandrel to said bracket, said spring having an elongated slot including a portion disposed in a plane common to the bite of said coils;'and means for guiding a yarn for passage through said slot and into the bite of said coils.

9. A yarn tensioning device, comprising: a pair of mandrels; a spring having the ends thereof wound in opposite directions upon said mandrels to form coils'having outermost convolutions forcibly urged toward each other; a support; means mounting one of said mandrels on said support in relatively nonrotatable' relation thereto; means mounting the other of said mandrels on said support for free rotation relative thereto; and means for guiding a yarn into position between the confronting convolutions of said coils.

10. A yarn tensioning device as defined in claim 9, in

which the spring is a variable tension spring, and where in means is provided for adjusting oneof the mandrels to effect winding and/or unwinding ofa portionof said spring relative thereto. p

, 11. 'Ayarn tensioning device,'; comprising: apair of mandrels; a spring having the ends thereof wound in opposite directions upon said mandrels to form coils having outermostconvolutions forcibly urged toward each other; a support; means mounting said mandrels on-said' support; means for guiding a yarn into position between 'the outermost convolutions of said coils; and means including a yarn feeding finger connected flwithone of 'said mandrels arranged to overcome the force of. the spring and effect partial unwinding of the coil associated'therewith when the tension in the yarn fedby said finger exceeds a predetermined amount.

12. A yarn tensioning device, comprising: a pair ofmandrels; aspring having the ends thereof wound in opposite directionsupon said mandrels to form coils having outermost convolutions forcibly urged toward each'other; a support; meansmounting said mandrels on said support for rotation relative thereto; means for. rotatably adjusting one of saidmandrels relative to the other; means for locking said one mandrel in'adjustedposition; and means for guiding a yarn into position between the outermost convolutions of said coils. I I t 13. A yarn tensioning device as defined in claim 12, in which the adjusting means includes a knob connected with said one mandrel for rotatably adjusting the same, and the locking means includes a ratchet wheel connected with said one mandrel and pawl engageable with said ratchet.

14. A yarn tensioning device, comprising: a pairof mandrels; a variable tension spring having the ends there of wound in oppositedirections upon said mandrels to form coils having-outermost convolutions forcibly urged toward each other; a supportrtneans mounting said mandrels on said support for rotation relative thereto; means for rotatably adjusting oneof said mandrels relative to the other; means for locking said one mandrel in adjusted posi tion; means for guiding a yarn into position between the outermost convolutions of said coils; and means including a yarn feeding finger connected with said other mandrel arranged to overcome the force of the'spring and effect partial unwinding of the coil associated therewith when the tension in the yarn fed by said finger exceeds a predetermined amount.

15. A yarn tensioning device, comprising; a pair-of 7' mandrels; a variable tension spring having the ends there to overcome the force of the spring and eifect partial unwinding of the coil associated therewith when the tension in the yarn fed by said fingerexceeds a predetermined amount. V

References Cited in the file of this patent UNITED STATES PATENTS 713,124 Lundquist Nov. 11, 1902 727,429 Patterson May 5, 1903 2,420,513 Arrowood May 13, 1947 FOREIGN PATENTS 837,228

Germany Apr. 21,1952 

